Stop mechanism for sewing-machines.



J. WHITELAW.

sToP MEcHAmsM FQ'R SEWING MACHINES.

` APPLICATION FILED AUG-27. 19|4.

IPatented' July 18,1916;

3 SHEETS-SHEET 1.

`1. wHlTELAw. STOP MECHANISM FOR SEWI'NG MACHINES.

APPucATloN FILED Aue'.27. 1914.

l Patented July 18, 1916.

' SSHEETS-SHEETZ.

I. WIIITELAW.

STOP MECHANISM FOR SEWING MACHINES. APPLICATION FILED AUG.27. I9I4.

- 3 SHEETSv-SHEETQ- da 6'.

17a/7565 www MQIW UNITED STATES PATENT oEEroE.l

JAMES WHITELAW, orv

ST. LOUIS, MISSOURI.

STOP MECHANISM FOR SEWING-MACHINES.

Application ined August 27,

T o all whom z't may concern.:

Be' it known that I, JAMESYWHITELAW, a citizen of the United States,residing at St. Louis, in the State of Missouri, have invented certainnew and useful Improvements 1n Stop Mechanism for Sewing-Machines, of

' which the following is a specification.

` operation without injurious jar or shock to the arrested mechanism. A.

A further object of my invention 1s to provide a construction of thecharacter de scribed employing jointly and cooperatively a yielding,self-returning stop-member and a brake actuated thereby, both acting onthe parts to be' arrested, so that the progression l of the moving partspast the cyclic point in their movement where the stopping devices` arethrown into action is short, and the arrested, parts are spring-returnedto their position of rest. f

Another object of my invention is to simplify and improve theconstruction of Stop motion devices for sewing machines and the like bynovel correlation of clutching, stopping, stop-timing and operatingmechanisms; and to improve in construction the elements andsub-combinations thereof.

In the drawings wherein -I have illustrated a single embodiment of myinvention as applied to a sewing machine, for purposes o f fulldisclosure` Figure 1 is an illustration, diagrammatic in parts, of asewlng machine, equipped with stop-motion andpower transmission meansembodying my invention; Fig. 2 is an extended perspective of thestop-motion and clutch parts; Fig. '3 is aY vertical, longitudinalsection therep through; Fig. 4 is a perspective detail of a clutch part;Fig. 5 is a perspective detail of a connector part.; Figs.v 6, 7 and 8are sections on lines 6--6, 7-7 and 8 8 of Fig. 3;

Fig. 9 is a section on line9-9 of Fig. 1.

In the drawings 10 indicates. the main shaft of a sewing machine and bthe fixed bearing at its power receiving end, beyond which the shaftprojects .toreceve thestop Specication of Letters Patent.

1914. Serial No. 858,807.

motion and clutch devices. In the particular construction shown, a block11-is keyed at l2 to the shaft to rotate therewith. It carries,relatively, theaxially shiftable means that throws into action thepowerwheel clutch and the shaft-arresting means. The axially shiftableconnector shown is a stifl'l baror key, 13, slidable axially in a groove14 provided therefor lin block 11 and Patented July 18,1916'.

shiftable by the bell crank shifter-lever 15.

through .the intermediary of the conventional shifter yoke 16 and,grooved shifter vmember br controller 17, the latter secured as by screw18'to theA shiftable bar 13. When moved to the right,v (Figs.v2 and 3,)

the shiftable member or connector, 13, sets a i clutch that connectspower wheel 20 with the shaft 10; and when moved to the left saidconnector member throws the shaftstopplng appliances into action.

Power wheel 20 is loosely mountedy on the shaft 10-between the fast endcollar 20a and the fast block 11, said wheel having in its inwardlyfacing hub .20 an annular recess 21 receiving-the reduced annularextension 11 of the block l1. In the annular clearance between theparallel surfaces 'of extension 11 and the outer wall of hub 20 is anexpansible clutch-band 22 that rides in rotation with the fast block 11.In the particular construction shown the split clutch band 22, undernormal tension, frees the power wheel 20, but it is expansible by theconnector 13 to make fast frictional engagement.

with the power wheel and so, through the clutch, the connector memberand the block 11, to communicate motion tothe shaft 10.

Specifically the confronting end-'walls 22 of the split clutch-ringconverge outwardly and in the wider portion of this tapered Islit-*spacethere normally lies the outer end of' the connector member 13, so thatthe clutch-band is positively carried in rotation with the' shaft 10 atall times. The' walls of the connector member confronting the convergingwalls 22"of the clutch member are. .y

recessed and provided with spring-positioned anti-'frictional rollers23, so that whenv` the clutch member isl moved to the right saidrollers, riding along the converging faces 22 expand the clutch-band.This condition is shown in Fig. 3.

It will be observed that by the specific construction shown I am able toprovide a veryefectively-working friction clutch, operable on relativelyshort movementv of the `(.:on-

1T receives a movable brake member, pref-` erably in the form of a splitband 25 having one end rigidly mounted, through standard 2G andbolt'iZT, on a suitable part of the machine frame, and at its free end,arranged for compression-applying movement to be controlled by connector13. Specifically the free end of the brake band carries a spring housingb() recessed to receive a compression spring 31 through which thebrake-setting pressure is applied. Through the hous-` ing and springpasses a rod 32 having at its upper end a head 33 and at its lower end,

where it passes through the bottom of the housing, receiving theadjusting nut 31. Obviously, down 'ard pressure on head 33 will compressthe spring and through the spring tension'will tend to set the brake,and when the connector-member 13 is appropriately moved to. the left itserves to communicate power from the main shaft to the spring-head 33 tocause the depression of the spring-head.

As an intermciliary between the controller member and the brake settingspring I preferably provide a striker member 40, and preferablyassociate with said striker a timing member or guard structure 41 thatinsures proper co-action of the connector 13 and the striker. Whenpermitted by the guard 41, connector member 13 may positively engage thestriker 40, to carry it in rotation and cause it functionally to actupon the brake-setting spring.

1n the specific construction shown,striker member 1() is a plate looseon the shaft 1'0 and interposed between the inner end of block 11 andthe bearing block Y) or other appropriate part of the machine frame. Thestriker is capable of oscillatory movement to an extent limited byengagement of a pin 42 on the machine frame in a slot 43 of the striker,and it has a laterally bent finger 44 overhanging the head 33 of thebrake-applying` spring, by which said striker is normally held in raisedposition as shown in Figs. 7 and 8. The b'ake construction is so locatedthat the spring stands substantially tangential to the path of movenientof the striker-tinger 44. At a` suitable point in its periphery thestriker is provided with a notch l5 of suitable depth to receive a head13 of the connector-member 13. and in rear of the notch the perimeterbfthe plate is cut down smaller than the maximum radius of head 13', asshown at i6. The annular surface of said striker plate in the axial pathof said head 13. is preferably tapered or gradually thinned in a spiral11T leading downward into the notch 15. If the head 13 of the controller13 be pressed to the left, to make contact with the annular surface ofthe striker -LO a suitable time, or considerably number of degrees,before the controller reaches notch 45, said controller head will glidedown the tapered surface 17 and make positive, square engagement withthe leading end l5 of the notch -t so as to carry the striker rotativelywith the shaft to compress the spring 32 and set the brake. It isimportant, however, in a machine wherein the rotating parts moverapidly, as in a high speed sewing-machine, that provision be made toinsure that the connector 13 shall either make good, substantial contactwith the notch wall 45 or shall not engage the notch at all; this toprevent battering up of the acting surfaces of the two parts, and otherinjury to the machine, by partial or ineffective engagement thereof. Tothis end the guard or timer Ll1 is provided. In the speciflcconstruction shown said guard takes the form of a met-al shield-piecepivoted between its ends, as at 50, to the extended finger of thestriker, and acted on by a spring 51, interposed between its rear endand the striker, so that its forward or leading end, (which ispreferably slightly thicker than the thickness of the striker member10,) may normally rest uponthe suitably-reduced perimeter 46 of thestriker plate 40 partially to close the notch 45. The receiving end ofthe guard is curved outwardly so that its end is located radially beyondthe rota- .tive path of head 13 of the Connector, and

is provided with a tooth 53 with its receiving surface inclined` and itsfront edge squared, spaced apart from the wall 15 of the striker by thewidth of connector-head 13. Consequently. if the key or connector 13 bemoved to the left to function with the striker at a time, in therotation of the main shaft, before its head 13 axially registers withthe guard member 41, the connectorhead, following down the inclinedsurface l? of the striker, will pass freely under the receiving end ofthe guard, and.` cooperating with the inclined portion 52 of the guard,will tilt the guard outwardly so that obviously the, connector head may;proceed un- `interruptedly under the tooth "53 and into engagement withthe notch 45 of the striker. In such positoin it is fixed in relation tothe striker, by wall 45 on the one side, tooth 53 on the other. But ifthe connector head vhas passed rotatively beyond the receiving end 52 ofthe guard 41 before the effort is made to engage the connector with thestriker plate. then, as indicated iu dotted lines in Fig. S, the sidesurface of the guard -out making effective engagement with the,

striker. Ofcourse when the operator is thus trying to stop themachinet-he neXt revolution of the main shaft will bring about the desiredresult.

My stop motion construction may, of`

course, be applied to many forms of sewingmachines and many machines forother purposes, and its shifter yoke, or equivalent part, may beoperated y in` any suitable fashion. In Fig. 1,however', I have showndiagrammatically parts of a machine for blind stitching of the generaltype known as the' Lewis machine, and in said illustration p representsdiagrammatically a rigid presser foot, w a movable work handlingmechanism below the presser foot, susceptible of being depressed againstthe tension of spring s to permit insertionY of thework. In suchinstallations I prefer that the connections for ooerating thestop motioncontroller be combined with the connectionsfor operating the workhandling mechanism, and in the specific construction shown the bellcrank shifter lever 15 has link connections 60 with arocking gate 61pivotally carried by a longitudinal' shaft 62 of the machine, said gatehaving a lever arm 63 extending therefrom in the path of movement of arocker. 64 that also works on spring s to control depression of the workhandlingmechanism w, said rocker being provided with a connection 67extending to. any suitable lift or foot treadle. A spring 69 interposedbetween the bell-crank shifter-lever 15 and the part of :fi-ector member18, rotatable with, but slid-4` able axially on, the main shafts, isthrown to the right, its antifrictional rollers 12 'spread i the bandclutch 22 making effective clutchA engagement with the power wheel 20 sothat power is applied to the main shaft 10. lVhen the slidableconnector' or key 13 is moved. to the left during such part of the cycleof rotation of the main shaft that the head 13 of the connector may notstrike upon the side surface of the timer guard 41, the left end of theconnector will follow the incline 47 of the striker plate, 40` movingthe guard 41 on'V its pivot, and the connector end will make positive'engagement in the notch 45. Then the shaft is thus freed from theclutch and positively connected with tlic'strikeifLO, it

carries the latter around through a few degrees of rotation, the finger44 `of the striker acting on spring head 38 to compress the spring 32that vis carried by the brake band. This action I have found` inpractice to be highly effective. By the combined action of the 'yieldingspring and the friction brake the shaft is stopped substantially withoutjar or shock injurious to the machine. hOf course the higher the speedof the machine the further the spring will be compressed and the quickerwill the'spring band V,be applied; but when the spring has acted and.has received. its compresslon, 1t returns the striker to its normalposition, turning the shaft backward a fewdegrees. The return movementof thestrikeris limited by slot 43, and it will be noted, tooth 53prevents overthrowing of the shaft due to the back-kick of spring 32 so*that the shaft-stoppage is uniform, and its final position `of rest isthe same whatever may have been its running velocity. In a sewingmachine, of course, this position at which the shaft is stopped is suchthat the needle isout ofthe goods, so that when the work handlingdevices are properly' positioned the goods may be free formanualmovement.

claim is 1. In a stop motion for stopping a shaft at y Having describedmy invention, AwhatI apredetermined rotating position, the com- 2. In astop motion, the combination of a rotatable shaft, aloose striker, aspring for opposing rotation of said striker, means carriedk inrotationby the shaft, axially shift-ll able thereon to engage or disengage saidstriker, and means to prevent engagement of said shiftable means andthestriker during a predetermined portion of the cycle of rotation of theshaft.

'3. In a stop motion of the character described, the combination vof. ashaft, brake means therefor including a band brake, and a brakesettingcompression spring, a Striker loose on the shaft arranged-forcooperation with said springto compress said. spring and set said brake4when said striker' is turned with the shaft, and means on the shaft,carried in rotation therewith, to move'k the striker, the last saidmeans and the striker relatively movable to engage or disengage them.v

y 4. In a stop motion of the scribed, the coml'iination of a shaft,irake character de- "part for` coaction with. the Ispring movmeans,therefor including a band brake, and we a brake setting compressionspring, a striker loose on the shaft arranged for cooperation with saidspring to compress said spring and set said brakeV when said striker isturned with the shaft, means on the shaft, carried in rotationtherewith, to move the striker, the last said means and the strikerrelatively movable to engage or disengage them, and a guard member forpreventing engagement of said means with the striker during apredetermined portion of the rotating cycle of the main shaft.

5. In a device of the character described, the combination of a shaft,a` loose power wheel thereon having an inwardly facing recess, a splitcircumferentially expansible clutch-band within said recess rotatablewith the shaft, shaft stopping means normally disconnected from theshaft, an axially shiftable member carried in rotation by the shaft,movable in one direction to expand said clutch-band and in the otherdirection to actuate said stopping means.

G. In a stop motion, a shaft, a loose part, means rotatively fast on theshaft axially shiftable thereon to engage said loose part; a.compression spring arranged tangentially to said loose part to becompressed thereby, and a band brake for the shaft comprising a splitring carrying a spring receiving socket at one end.

7. In a stop motion, a shaft, band-brake means therefor comprising asplit compression band fast at one end and loose at the other, andVhaving a spring-socket at its loose end, a coiled compression springcarried by said socket, and means rotatable with said shaftforcompressing said spring.

8. Ina stop motion, a shaft, a band-brake means therefor comprising asplit compression band' fast at one end and loose at the other, andhaving a spring socket at its loose end, a coiled compression springcarried by said socket, and means for compressing said spring comprisinga. loose striker and a connector rotatable with the shaft and axiallymovable to engage or disengage the striker.

9. In a stop-motion, the combination of a shaft, a block fast thereon, aconnector slidable in said block, a controller member fast on saidconnector, a shifter lever for said controller, a band brake coactingwith said controller member, a compression spring connected with thebrake to set it when the spring is tensioned, and a striker loose on theshaft, arranged to be engaged by the connector and, when so engaged,compress the spring.

10. In a stop motion for stopping a shaft at a predetermined rotatingposition, the combination with brake means for the shaft, of a. springcooperating with said brake to set the brake when the spring istensioned, a part for coaction with the spring movable rotatively withthe shaft to tension the spring, means for effecting cooperation of saidpart and spring, and means to prevent such cooperation during apredetermined interval in the cycle of shaft rotation commencingapproximately a quarter revolution in advance of the point ofcoperation.

l1. In a stop motion of the character described, the combination of ashaft, brake means therefor including a band brake, and a brake settingcompression spring, a striker loose on the shaft arranged forcooperation with said spring to compress said spring and set said brakewhen said striker is turned with the shaft, means rotatable with theshaft and axially movable to engage or disengage the striker, and aguard member pivoted to the striker' and lying in the rotary path of thelast said means for preventing engagement of said means with the strikerduring a predetermined portion of the rotating cycle of the main shaft.

In testimony whereof I hereunto set my hand in the presence of twosubscribing witnesses.

JAMES VVHITELAW.

In the presence of R. M. LAWRENCE, J onN D. Rirrnr.

